diff options
Diffstat (limited to 'arch/x86/kernel/module.c')
| -rw-r--r-- | arch/x86/kernel/module.c | 81 |
1 files changed, 64 insertions, 17 deletions
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c index 925179f871d..e69f9882bf9 100644 --- a/arch/x86/kernel/module.c +++ b/arch/x86/kernel/module.c @@ -15,6 +15,9 @@ along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/moduleloader.h> #include <linux/elf.h> #include <linux/vmalloc.h> @@ -25,24 +28,68 @@ #include <linux/mm.h> #include <linux/gfp.h> #include <linux/jump_label.h> +#include <linux/random.h> -#include <asm/system.h> #include <asm/page.h> #include <asm/pgtable.h> #if 0 -#define DEBUGP printk +#define DEBUGP(fmt, ...) \ + printk(KERN_DEBUG fmt, ##__VA_ARGS__) #else -#define DEBUGP(fmt...) +#define DEBUGP(fmt, ...) \ +do { \ + if (0) \ + printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ +} while (0) +#endif + +#ifdef CONFIG_RANDOMIZE_BASE +static unsigned long module_load_offset; +static int randomize_modules = 1; + +/* Mutex protects the module_load_offset. */ +static DEFINE_MUTEX(module_kaslr_mutex); + +static int __init parse_nokaslr(char *p) +{ + randomize_modules = 0; + return 0; +} +early_param("nokaslr", parse_nokaslr); + +static unsigned long int get_module_load_offset(void) +{ + if (randomize_modules) { + mutex_lock(&module_kaslr_mutex); + /* + * Calculate the module_load_offset the first time this + * code is called. Once calculated it stays the same until + * reboot. + */ + if (module_load_offset == 0) + module_load_offset = + (get_random_int() % 1024 + 1) * PAGE_SIZE; + mutex_unlock(&module_kaslr_mutex); + } + return module_load_offset; +} +#else +static unsigned long int get_module_load_offset(void) +{ + return 0; +} #endif void *module_alloc(unsigned long size) { if (PAGE_ALIGN(size) > MODULES_LEN) return NULL; - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, - GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC, - -1, __builtin_return_address(0)); + return __vmalloc_node_range(size, 1, + MODULES_VADDR + get_module_load_offset(), + MODULES_END, GFP_KERNEL | __GFP_HIGHMEM, + PAGE_KERNEL_EXEC, NUMA_NO_NODE, + __builtin_return_address(0)); } #ifdef CONFIG_X86_32 @@ -57,8 +104,8 @@ int apply_relocate(Elf32_Shdr *sechdrs, Elf32_Sym *sym; uint32_t *location; - DEBUGP("Applying relocate section %u to %u\n", relsec, - sechdrs[relsec].sh_info); + DEBUGP("Applying relocate section %u to %u\n", + relsec, sechdrs[relsec].sh_info); for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { /* This is where to make the change */ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr @@ -74,11 +121,11 @@ int apply_relocate(Elf32_Shdr *sechdrs, *location += sym->st_value; break; case R_386_PC32: - /* Add the value, subtract its postition */ + /* Add the value, subtract its position */ *location += sym->st_value - (uint32_t)location; break; default: - printk(KERN_ERR "module %s: Unknown relocation: %u\n", + pr_err("%s: Unknown relocation: %u\n", me->name, ELF32_R_TYPE(rel[i].r_info)); return -ENOEXEC; } @@ -98,8 +145,8 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, void *loc; u64 val; - DEBUGP("Applying relocate section %u to %u\n", relsec, - sechdrs[relsec].sh_info); + DEBUGP("Applying relocate section %u to %u\n", + relsec, sechdrs[relsec].sh_info); for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { /* This is where to make the change */ loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr @@ -111,8 +158,8 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, + ELF64_R_SYM(rel[i].r_info); DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", - (int)ELF64_R_TYPE(rel[i].r_info), - sym->st_value, rel[i].r_addend, (u64)loc); + (int)ELF64_R_TYPE(rel[i].r_info), + sym->st_value, rel[i].r_addend, (u64)loc); val = sym->st_value + rel[i].r_addend; @@ -141,7 +188,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, #endif break; default: - printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n", + pr_err("%s: Unknown rela relocation: %llu\n", me->name, ELF64_R_TYPE(rel[i].r_info)); return -ENOEXEC; } @@ -149,9 +196,9 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, return 0; overflow: - printk(KERN_ERR "overflow in relocation type %d val %Lx\n", + pr_err("overflow in relocation type %d val %Lx\n", (int)ELF64_R_TYPE(rel[i].r_info), val); - printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n", + pr_err("`%s' likely not compiled with -mcmodel=kernel\n", me->name); return -ENOEXEC; } |